The first is a small 1,600 square metre slice of land on Grey Street at South Brisbane beside South Brisbane station.

This purchase will allow the new underground busway station to be built directly beneath the busy Melbourne and Grey Street intersection.

The second is a 4.5-hectare block of land at Rochedale that will become the new depot for the 60 Brisbane Metro "articulated buses".

Lord Mayor Graham Quirk confirmed on Tuesday night talks were underway with Queensland Rail to buy the small portion of land beside the heritage-listed, red-brick South Brisbane rail station.

Brisbane Metro plans show $20 million is set aside to acquire this parcel of land, which many years ago was to be sold for a hotel complex, plus the second site at Rochedale.

The Brisbane Metro station would sit underground - diagonally - under the Grey and Melbourne Street block of land.

The underground service would spread underneath the forecourt of the Queensland Performing Arts Complex and allow articulated buses to connect to the South East Busway.

"It will mean the metro vehicles will no longer enter and exit the busway from the ???hole in the wall' in Melbourne Street," Cr Quirk explained on Tuesday night.

From the city side, the Brisbane Metro elongated buses would go along the Victoria Bridge down to an underground Cultural Centre Metro busway station, beneath the Grey and Melbourne street intersection.

The plans also propose a low-height hotel could be built above the Brisbane Metro at the Grey Street site.

A snapshot of the Brisbane Metro station

• The new underground station will be approximately 120 metres long
• It will be about 35 metres wide
• It will be roughly seven metres below Grey Street
• There will be Go-Card ticket gates at the surface entries.
• The Metro elongated buses will rise up from the South Brisbane underground busway to the Victoria Bridge.
• Lifts, stairs and escalators are planned to allow commuters to get to Metro busway.

What will happen to the existing Victoria Bridge bus services?

• The Cultural Centre bus station will need to be demolished and reconstructed on a new alignment.
• The two Brisbane Metro lanes will be repositioned to the centre of the Victoria Bridge.
• The non-metro bus lanes will go either side of the Brisbane Metro lanes.
• The bridge will be closed to road traffic.

Deputy Mayor Adrian Schrinner said council needed the 1.6-hectare site at Grey Street for Brisbane Metro plans to go ahead.

"This will provide a dedicated connection for metro vehicles and buses and allow the closure of the existing Melbourne Street portal, significantly reducing bus numbers at street level," he said.

Meanwhile, Brisbane City Council has chosen a depot site at Rochdale for 60 metro vehicles.

The 45-hectare block of land is beside Pacific Motorway, south of where the Gateway Motorway crosses the Pacific Motorway.

"Council is getting on with the job and has identified land required for the project's depot at Rochedale that provides direct access to the Eight Mile Plains busway station where the Metro line begins," Cr Quirk said.

On Wednesday Queensland opposition leader Tim Nicholls committed, if elected, $20 million of state government land for the metro and a $10 million investment to explore metro extensions into Springwood, Coorparoo and Chermside.

"As part of working with the council we are prepared, if elected, to support the project by ensuring that the land that is necessary for this project to go ahead is made available at no cost to the council," Mr Nicholls said.

"This is a real plan the council has put forward and it's a plan the LNP if elected will support and give commuters and public transport users better transport options here in the southeast."

The $944 million Brisbane Metro will run over 21 kilometres with two new high-frequency, high-capacity lines, linking Eight Mile Plains to Roma Street and Royal Brisbane and Women's Hospital to the University of Queensland Lakes and all busway stations in between.

Work has already begun on the project with on-site monitoring and testing at various locations adjacent to the Brisbane Metro routes, including the Mater Hospital, the Queensland Performing Arts Complex, City Hall and the Royal Brisbane and Women's Hospital.

Results from these tests will be part of the benchmark when the concept design is released in November.